I am a new Linux user. I use scp to upload files to net-storage provided CDN company. I do not want to overwrite the existing files. How can I prevent overwriting of files when using scp command under Linux, Mac OS X or Unix like operating systems?

I am a new vi / vim text editor user and I know how to quit without saving changes. What if I want to wipe out all of the edits I have made in a session and get back to the original file? How do I wipe all changes since opening a file?